I'm going to edit the practice area of your post to "Criminal Defense" for better exposure.
This attorney is licensed to practice law in the State of California. The laws of your jurisdiction may differ and thus this answer is for informational and educational purposes only and is not to be considered as legal advice. Since all facts are not addressed in the question, this answer could change depending on other significant and important facts. This answer in no way constitutes an attorney-client relationship.
This sounds like a question that has recently been asked. The right question is whether the Commonwealth has enough evidence to prove beyond a reasonable doubt that you possessed the weapon. Retain an experienced criminal defense attorney and have them aggressively put them to their burden. Good luck.
I agree that this question seems to be a repeat. Exploring on the Internet questions of how or why police might/could charge you seems like a poor use of your time and energy. At least from this version, it is unclear whether you have been charged or not. If you haven't then stop worry about the academic issues you've raised. If you have been charged then the only real help will come from retaining an experienced criminal defense attorney in your area.